Process of producing isoprene.



UNITED STATES PATENT OFFICE.

LUCAS PETRON KYRIAKIIOES AND RICHARD BLAIR EARLE, OF BOSTONQTMASSACHU- SETTS, ASSIGNORS TO HOOD RUBBER COMPANY, OF BOSTON, MASSACHUSETTS, A

. CORPORATION OF MASSACHUSETTS.

- PROCESS OF PRODUCING ISOPBENE.

No Drawing.

ducing Isoprene, of which the following is a specification.

Our invention relates to a new and valuable process for producing isoprene (2 methylbutadiene l, 3; B methyldivinyl) which is a valuable hydrocarbon used in the preparation of rubber or terpenes.

The new process consists in passing the vapors of valeraldehyde of the formula:

CH3CHCHr- 3 over dehydrating catalytics such as aluminum silicate heated to temperatures from 400600 0., at pressures less than 60 millimeters of mercury.

In order to illustrate the new process more fully the following example is given:

Valeraldehyde of the formula:

CHB GHCHE CHB H0 is distilled slowly over aluminum silicate, either powdered or in briquet form, which is kept at atemperature -of 550 C. and a pressure of one millimeter of mercury by a vacuum pump. The products of the reaction are condensed in suitable receivers by means of refrigerating agents and purified by fractional distillation. Any'unc'hanged aldehyde is passed again over the catalytic as before.

The fraction boilin from 32.37 0. con- Speeification of Letters Patent.

'Application filed November 11, 1911 Patented July 23, 1912. Serial No. 659,827.

sists of nearly pure isoprene and may be used in this'state of purity.

The formation of isoprene takes place by the splitting off of water, according to the equation 0 11, 0 (3 H -i- H O.

The process is useful at the ordinary pressure but the yield is muchincreased by over dehydrating catalytics at temperatures T from 400 to 600 C., in mono, at pressures less than 60 millimeters of mercury.

2. The process for producing isoprene which consists in passing the vapors of the valeraldehyhe of the formula:

over aluminum silicate at temperatures from 400 to 600 0., in oamw, at pressures less than 60 millimeters of mercury.

In testimony whereof, we aflix our signatures in presence of two witnesses.

LUCAS 'PETRON KYRIAKIDES. RICHARD BLAIR EARLE.

Witnesses: JEssm R. Mo'rr, M. ALICE HAGARTY. 

